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Date: Fri, 11 Aug 2017 12:46:15 +0200
From: Christoph Hellwig <hch@lst.de>
Subject: Re: [PATCH v1 2/6] fs: use on-stack-bio if backing device has
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To: Dan Williams <dan.j.williams@intel.com>
Cc: Jens Axboe <axboe@kernel.dk>, Jan Kara <jack@suse.cz>, linux-mm <linux-mm@kvack.org>, "linux-nvdimm@lists.01.org" <linux-nvdimm@lists.01.org>, Dave Chinner <david@fromorbit.com>, Linux Kernel Mailing List <linux-kernel@vger.kernel.org>, Matthew Wilcox <willy@infradead.org>, Christoph Hellwig <hch@lst.de>, Minchan Kim <minchan@kernel.org>, kernel-team <kernel-team@lge.com>, seungho1.park@lge.com, Andrew Morton <akpm@linux-foundation.org>, "karam . lee" <karam.lee@lge.com>
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On Wed, Aug 09, 2017 at 08:06:24PM -0700, Dan Williams wrote:
> I like it, but do you think we should switch to sbvec[<constant>] to
> preclude pathological cases where nr_pages is large?

Yes, please.

Then I'd like to see that the on-stack bio even matters for
mpage_readpage / mpage_writepage.  Compared to all the buffer head
overhead the bio allocation should not actually matter in practice.
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